Cellphone/Camera Stalk Perch for MK3S  

Cellphone/Camera Stalk Perch for MK3S

I need to be able to monitor my printer from other rooms.  I intend to use an old cell phone as a camera.  But I will need something to clamp a cellphone stalk (one of those gooseneck stalks which clamps onto the phone at one end and clamps on to something else - e.g. a table top - at the other end) to.  So I am thinking about a length of t-slot, fixed perpendicular to the existing piece of t-slot which forms the right side of the MK3S frame, and thus sticking out to the right horizontally.  The gooseneck stalk would clamp onto the added piece of t-slot - i.e. the perch.  I've attached a photo of the existing piece of t-slot I am talking about.  Although I have to admit that in the photo it does not look much like t-slot.

My question:  I am new to the t-slot concept (but very intrigued by it).  Can I purchase any old piece of t-slot and auxiliary pieces (mainly two right angle braces) and it will work?  Or are there size and configuration things I have to worry about?  I have learned that it comes in different sizes and I know that the piece I would be attaching to is 30mm square.  I guess my main concern the the size of the slot.  Are they all the same?  AND what's a good source for t-slot parts for a hobbyist?  Someone who will sell me just a 6-8" length and a few braces, screws, etc. ?

ALSO does anyone know if I will be able to make the t joint (to join the perch to the existing t-slot in the MK3S frame) without any disassembly of the MK3S or drilling any holes in the existing t-slot?  In everything I have seen so far on YouTube every assembly seems to involve either drilling a hole or sliding a nut into the t-slot from an open end.

Thanks,  Bob